Papers by Keyword: Fault Protection

Abstract: Power control technology of LED is proposed, which can be adaptive to the change of temperature while online. The input power of LED will be adjusted according to the current value and its change rate of LED radiator. Reducing input power can balance the decreasing of the capacity of heat dissipation caused by the rise of ambient temperature in order to keep radiator temperature in a safe range. This avoids the vicious circle of the temperature excursion of P-N Junction caused by the rise of the temperature of LED light source characteristic of negative temperature. This, in turn, avoids damage to LED at high temperature.

Abstract: This paper describes a simple fault protection system for Current Source Inverter built with normally-on SiC JFETs. Because all transistors are in on-state after loss of the gate drive(s) supply, list of possible fault modes is extended in reference to standard inverters. That is also why an additional normally off switch is introduced in the DC link. Operation principles of the protection system which follows the drain-source voltages of JFETs and the current of the DC link are presented. The 2kVA/100kHz model of the inverter equipped with the proposed system is validated via various laboratory tests including short-circuits and the auxiliary supply turn off.

Abstract: A model of the AC induction motor, which allows us to analyze all operation modes of motor supplied by the frequency converter, has been developed. A simulation of the inverter of the frequency converter and the AC induction motor interaction on the basis of the developed motor model, using software MATLAB, was performed and a motor regenerative braking mode was investigated. The results of investigation are used for the development of fault protection of the inverter.